The invention belongs to the technical field of cleaning and descaling in heat-exchange tubes and particularly provides a pair rubber ball for cleaning and descaling in the heat-exchange tubes. The pair rubber ball comprises two solid rotary bodies, elastic cleaning and descaling fins and a middle elastic connecting body. The elastic cleaning and descaling fins are evenly distributed on the circumference of the two solid rotary bodies, wherein the thickness of the fins is 0.6mm to 2mm, and the ratio between the height and thickness of the fins is 1.25 to 4; the two ends of the middle elastic connecting body are connected with the two solid rotary bodies, wherein the middle elastic connecting body of the pair rubber ball is particularly a cylindrical body, a flaky body or the compound of the cylindrical body and the flaky body, the diameter of the cylindrical middle elastic connecting body is 1/10 to 1/2 the inner diameter of the heat-exchange tubes, and the thickness of the flaky middle elastic connecting body is 1/25 to 1/5 the inner diameter of the heat-exchange tubes; and the error in the density of the solid rotary bodies and the density of the conveyance fluid is not larger than 8%. The invention has the advantages of good cleaning and descaling effects, low possibility of blocking the heat-exchange tubes and long service life.